Measurements of the fast electron bremsstrahlung during lower hybrid current drive in the HL-2A tokamak
Measurements of the fast electron bremsstrahlung during lower hybrid current drive in the HL-2A tokamak
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HL-2A 托卡马克低混合电流驱动期间快速电子轫致辐射的测量
作者：
Zhang Y P;Mazon D;Peysson Y;Malard P;Zhang P F;Zhang J;Zou X L;Zhou J;Xu H B;Bai X Y;Yang J W;Yuan G L;Song X Y;Li X;Zhong W L;Ding X T;Chen W;Li Y G;Hoang T;Delpech L;Ekedahl A;Isobe M;Song X M;Lu B;Liu Yi;Shi Z B;Yang Q W;Xu M;Duan X R;Liu Y
低杂波（LH）电流驱动（LHCD）等离子体中的快电子物理是一个非常重要的问题，因为这些粒子在逃逸电子（RE）产生和低杂波（LHW）相关物理中起着重要作用。HL-2A托卡马克实验采用了一种新的硬X射线针孔照相机，致力于加深对快电子和低杂波物理的理解。用HXR相机测量了HXR能量范围在20 ~ 200 keV的快电子韧致辐射（FEB）。为了研究LHW产生的快电子到RE的转换，LHW的非常短的脉冲，所谓的“blip”，具有5 ms的持续时间被注入到等离子体中在当前的平顶阶段。一个强大的增强RE诱导的blip注射。HXR相机的测量结果表明，LHWs产生的快电子主要集中在40-60 keV之间，这与基于朗道阻尼理论的计算值吻合较好。这些种子电子的能量高于临界逃逸能量。这种现象可能是由于Dreicer和雪崩RE产生的协同作用。此外，测量结果表明，在LHCD过程中的快电子的空间分布有一个峰值的轮廓，这意味着快电子主要产生在等离子体的核心。低杂波（LH）电流驱动（LHCD）等离子体中的快电子物理是一个非常重要的问题，因为这些粒子在逃逸电子（RE）的产生和低杂波（LHW）相关物理中起着重要的作用。HL-2A托卡马克实验采用了一种新的硬X射线针孔照相机，致力于加深对快电子和低杂波物理的理解。用HXR相机测量了HXR能量范围在20 ~ 200 keV的快电子韧致辐射（FEB）。为了研究LHW产生的快电子到RE的转换，LHW的非常短的脉冲，所谓的“blip”，具有5 ms的持续时间被注入到等离子体中在当前的平顶阶段。一个强大的增强RE诱导的blip注射。HXR相机的测量结果表明，LHWs产生的快电子主要集中在40-60 keV之间，这与基于朗道阻尼理论的计算值吻合较好。这些种子的能量...
Physics related to fast electrons in lower hybrid (LH) current drive (LHCD) plasma is a very important issue, since these particles will play an important role in runaway electron (RE) generation and lower hybrid wave (LHW)-related physics. Utilizing a new hard X-ray (HXR) pinhole camera, recent HL-2A tokamak experiments have devoted to enhancing the understanding of the physics on fast electrons and LHW. The fast electron bremsstrahlung (FEB) emission in the HXR energy range between 20 and 200 keV was measured by the HXR camera. To study the conversion of LHW-produced fast electrons into REs, a very short pulse of LHW, so-called “blip”, with duration of 5 ms was injected into the plasma during the current flattop phase. A strong enhancement of REs was induced by the blip injection. Measurements from the HXR camera show that the fast electrons generated by LHWs is mainly concentrated in 40-60 keV, which is well consistent with the calculated value based on Landau damping theory. The energy of these seed electrons is higher than the critical runaway energy. This phenomenon may be come from the synergetic effects of Dreicer and avalanche RE generation. Moreover, the measurements indicate that the spatial distribution of the fast electrons during LHCD has a peaked profile, implying that the fast electrons are mainly produced in the plasma core. It also suggests that the energy of the LHW mainly deposited in the plasma core region.Physics related to fast electrons in lower hybrid (LH) current drive (LHCD) plasma is a very important issue, since these particles will play an important role in runaway electron (RE) generation and lower hybrid wave (LHW)-related physics. Utilizing a new hard X-ray (HXR) pinhole camera, recent HL-2A tokamak experiments have devoted to enhancing the understanding of the physics on fast electrons and LHW. The fast electron bremsstrahlung (FEB) emission in the HXR energy range between 20 and 200 keV was measured by the HXR camera. To study the conversion of LHW-produced fast electrons into REs, a very short pulse of LHW, so-called “blip”, with duration of 5 ms was injected into the plasma during the current flattop phase. A strong enhancement of REs was induced by the blip injection. Measurements from the HXR camera show that the fast electrons generated by LHWs is mainly concentrated in 40-60 keV, which is well consistent with the calculated value based on Landau damping theory. The energy of these seed e...